Photoactive compounds

ABSTRACT

The present application relates to a compound of formula AiXi where Ai is an organic onium cation; and Xi is an anion of the formula X—CF 2 CF 2 OCF 2 CF 2 —SO 3   − . The compounds are useful as photoactive materials.

FIELD OF INVENTION

The present invention relates to novel photoactive compounds useful inphotoresist compositions in the field of microlithography, andespecially useful for imaging negative and positive patterns in theproduction of semiconductor devices, as well as photoresist compositionsand processes for imaging photoresists.

BACKGROUND OF THE INVENTION

Photoresist compositions are used in microlithography processes formaking miniaturized electronic components such as in the fabrication ofcomputer chips and integrated circuits. Generally, in these processes, athin coating of film of a photoresist composition is first applied to asubstrate material, such as silicon wafers used for making integratedcircuits. The coated substrate is then baked to evaporate any solvent inthe photoresist composition and to fix the coating onto the substrate.The photoresist coated on the substrate is next subjected to animage-wise exposure to radiation.

The radiation exposure causes a chemical transformation in the exposedareas of the coated surface. Visible light, ultraviolet (UV) light,electron beam and X-ray radiant energy are radiation types commonly usedtoday in microlithographic processes. After this image-wise exposure,the coated substrate is treated with a developer solution to dissolveand remove either the radiation exposed or the unexposed areas of thephotoresist. The trend toward the miniaturization of semiconductordevices has led to the use of new photoresists that are sensitive atlower and lower wavelengths of radiation and has also led to the use ofsophisticated multilevel systems to overcome difficulties associatedwith such miniaturization.

There are two types of photoresist compositions: negative-working andpositive-working. The type of photoresist used at a particular point inlithographic processing is determined by the design of the semiconductordevice. When negative-working photoresist compositions are exposedimage-wise to radiation, the areas of the photoresist compositionexposed to the radiation become less soluble to a developer solution(e.g. a cross-linking reaction occurs) while the unexposed areas of thephotoresist coating remain relatively soluble to such a solution. Thus,treatment of an exposed negative-working resist with a developer causesremoval of the non-exposed areas of the photoresist coating and thecreation of a negative image in the coating, thereby uncovering adesired portion of the underlying substrate surface on which thephotoresist composition was deposited.

On the other hand, when positive-working photoresist compositions areexposed image-wise to radiation, those areas of the photoresistcomposition exposed to the radiation become more soluble to thedeveloper solution (e.g. a rearrangement reaction occurs) while thoseareas not exposed remain relatively insoluble to the developer solution.Thus, treatment of an exposed positive-working photoresist with thedeveloper causes removal of the exposed areas of the coating and thecreation of a positive image in the photoresist coating. Again, adesired portion of the underlying surface is uncovered.

Photoresist resolution is defined as the smallest feature, which theresist composition can transfer from the photomask to the substrate witha high degree of image edge acuity after exposure and development. Inmany leading edge manufacturing applications today, photoresistresolution on the order of less than one-half micron are necessary. Inaddition, it is almost always desirable that the developed photoresistwall profiles be near vertical relative to the substrate. Suchdemarcations between developed and undeveloped areas of the resistcoating translate into accurate pattern transfer of the mask image ontothe substrate. This becomes even more critical as the push towardminiaturization reduces the critical dimensions on the devices. In caseswhere the photoresist dimensions have been reduced to below 150 nm, theroughness of the photoresist patterns has become a critical issue. Edgeroughness, commonly known as line edge roughness, is typically observedfor line and space patterns as roughness along the photoresist line, andfor contact holes as side wall roughness. Edge roughness can haveadverse effects on the lithographic performance of the photoresist,especially in reducing the critical dimension latitude and also intransferring the line edge roughness of the photoresist to thesubstrate. Hence, photoresists that minimize edge roughness are highlydesirable.

Photoresists sensitive to short wavelengths, between about 100 nm andabout 300 nm are often used where subhalfmicron geometries are required.Particularly preferred are photoresists comprising non-aromaticpolymers, a photoacid generator, optionally a dissolution inhibitor, andsolvent.

High resolution, chemically amplified, deep ultraviolet (100-300 nm)positive and negative tone photoresists are available for patterningimages with less than quarter micron geometries. To date, there arethree major deep ultraviolet (UV) exposure technologies that haveprovided significant advancement in miniaturization, and these uselasers that emit radiation at 248 nm, 193 nm and 157 nm. Photoresistsused in the deep UV typically comprise a polymer which has an acidlabile group and which can deprotect in the presence of an acid, aphotoactive component which generates an acid upon absorption of light,and a solvent.

Photoresists for 248 nm have typically been based on substitutedpolyhydroxystyrene and its copolymers, such as those described in U.S.Pats. No. 4,491,628 and 5,350,660. On the other hand, photoresists for193 nm exposure require non-aromatic polymers, since aromatics areopaque at this wavelength. U.S. Pat. No. 5,843,624 and GB 2,320,718disclose photoresists useful for 193 nm exposure. Generally, polymerscontaining alicyclic hydrocarbons are used for photoresists for exposurebelow 200 nm. Alicyclic hydrocarbons are incorporated into the polymerfor many reasons, primarily since they have relatively highcarbon:hydrogen ratios which improve etch resistance, they also providetransparency at low wavelengths and they have relatively high glasstransition temperatures. Photoresists sensitive at 157 nm have beenbased on fluorinated polymers, which are known to be substantiallytransparent at that wavelength. Photoresists derived from polymerscontaining fluorinated groups are described in WO 00/67072 and WO00/17712.

The polymers used in a photoresist are designed to be transparent to theimaging wavelength, but on the other hand, the photoactive component hasbeen typically designed to be absorbing at the imaging wavelength tomaximize photosensitivity. The photosensitivity of the photoresist isdependent on the absorption characteristics of the photoactivecomponent, the higher the absorption, the less the energy required togenerate the acid, and the more photosensitive is the photoresist.

SUMMARY OF THE INVENTION

The present invention relates to a compound of the formulaAiXi,where Ai is an organic onium cation; andXi is anion of the formula X—CF₂CF₂OCF₂CF₂—SO₃ ⁻, where X is selectedfrom halogen, alkyl, alkoxy and aryloxy;where Ai is selected from

andY—Arwhere Ar is selected from

naphthyl, or anthryl;Y is selected from

where R₁, R₂, R₃, R_(1A), R_(1B), R_(2A), R_(2B), R_(3A), R_(3B),R_(4A), R_(4B), R_(5A), and R_(5B) are each independently selected fromZ, hydrogen, OSO₂R₉, OR₂₀, straight or branched alkyl chain optionallycontaining one or more O atoms, monocycloalkyl or polycycloalkyl groupoptionally containing one or more O atoms, monocycloalkyl- orpolycycloalkylcarbonyl group, aryl, aralkyl, arylcarbonylmethyl group,alkoxyalkyl, alkoxycarbonylalkyl, alkylcarbonyl, monocycloalkyl- orpolycycloalkyloxycarbonylalkyl with the cycloalkyl ring optionallycontaining one or more O atoms, monocycloalkyl- orpolycycloalkyloxyalkyl with the cycloalkyl ring optionally containingone or more O atoms, straight or branched perfluoroalkyl,monocycloperfluoroalkyl or polycycloperfluoroalkyl, straight or branchedalkoxy chain, nitro, cyano, halogen, carboxyl, hydroxyl, sulfate,tresyl, or hydroxyl;R₆ and R₇ are each independently selected from straight or branchedalkyl chain optionally containing one or more O atoms, monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms,monocycloalkyl- or polycycloalkylcarbonyl group, aryl, aralkyl, straightor branched perfluoroalkyl, monocycloperfluoroalkyl orpolycycloperfluoroalkyl, arylcarbonylmethyl group, nitro, cyano, orhydroxyl or R₆ and R₇ together with the S atom to which they areattached form a 5-, 6-, or 7-membered saturated or unsaturated ringoptionally containing one or more O atoms;R₉ is selected from alkyl, fluoroalkyl, perfluoroalkyl, aryl,fluoroaryl, perfluoroaryl, monocycloalkyl or polycycloalkyl group withthe cycloalkyl ring optionally containing one or more O atoms,monocyclofluoroalkyl or polycyclofluoroalkyl group with the cycloalkylring optionally containing one or more O atoms, ormonocycloperfluoralkyl or polycycloperfluoroalkyl group with thecycloalkyl ring optionally containing one or more O atoms;R₂₀ is alkoxyalkyl, alkoxycarbonylalkyl, alkylcarbonyl, monocycloalkyl-or polycycloalkyloxycarbonylalkyl with the cycloalkyl ring optionallycontaining one or more O atoms, or monocycloalkyl- orpolycycloalkyloxyalkyl with the cycloalkyl ring optionally containingone or more O atoms;T is a direct bond, a divalent straight or branched alkyl groupoptionally containing one or more O atoms, divalent aryl group, divalentaralkyl group, or divalent monocycloalkyl or polycycloalkyl groupoptionally containing one or more O atoms;Z is —(V)_(j)—(C(X11)(X12))_(n)—O—C(═O)—R₈, where either (i) one of X11or X12 is straight or branched alkyl chain containing at least onefluorine atom and the other is hydrogen, halogen, or straight orbranched alkyl chain or (ii) both of X11 and X12 are straight orbranched alkyl chain containing at least one fluorine atom;V is a linkage group selected from a direct bond, a divalent straight orbranched alkyl group optionally containing one or more O atoms, divalentaryl group, divalent aralkyl group, or divalent monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms;X2 is hydrogen, halogen, or straight or branched alkyl chain optionallycontaining one or more O atoms;R₈ is a straight or branched alkyl chain optionally containing one ormore O atoms, a monocycloalkyl or polycycloalkyl group optionallycontaining one or more O atoms, or aryl;X3 is hydrogen, straight or branched alkyl chain, halogen, cyano, or—C(═O)—R₅₀ where R₅₀ is selected from straight or branched alkyl chainoptionally containing one or more O atoms or —O—R₅₁ where R₅₁ ishydrogen or straight or branched alkyl chain;each of i and k are independently 0 or a positive integer;j is 0 to 10;m is 0 to 10;and n is 0 to 10,the straight or branched alkyl chain optionally containing one or more Oatoms, straight or branched alkyl chain, straight or branched alkoxychain, monocycloalkyl or polycycloalkyl group optionally containing oneor more O atoms, monocycloalkyl- or polycycloalkylcarbonyl group,alkoxyalkyl, alkoxycarbonylalkyl, alkylcarbonyl, monocycloalkyl- orpolycycloalkyloxycarbonylalkyl with the cycloalkyl ring optionallycontaining one or more O atoms, monocycloalkyl- orpolycycloalkyloxyalkyl with the cycloalkyl ring optionally containingone or more O atoms, aralkyl, aryl, naphthyl, anthryl, 5-, 6-, or7-membered saturated or unsaturated ring optionally containing one ormore O atoms, or arylcarbonylmethyl group being unsubstituted orsubstituted by one or more groups selected from the group consisting ofZ, halogen, alkyl, C₁₋₈ perfluoroalkyl, monocycloalkyl orpolycycloalkyl, OR₂₀, alkoxy, C₃₋₂₀ cyclic alkoxy, dialkylamino,dicyclic dialkylamino, hydroxyl, cyano, nitro, tresyl, oxo, aryl,aralkyl, oxygen atom, CF₃SO₃, aryloxy, arylthio, and groups of formulae(II) to (VI):

wherein R₁₀ and R₁₁ each independently represent a hydrogen atom, astraight or branched alkyl chain optionally containing one or more Oatoms, or a monocycloalkyl or polycycloalkyl group optionally containingone or more O atoms, or R₁₀ and R₁₁ together can represent an alkylenegroup to form a five- or six-membered ring;R₁₂ represents a straight or branched alkyl chain optionally containingone or more O atoms, a monocycloalkyl or polycycloalkyl group optionallycontaining one or more O atoms, or aralkyl, or R₁₀ and R₁₂ togetherrepresent an alkylene group which forms a five- or six-membered ringtogether with the interposing —C—O— group, the carbon atom in the ringbeing optionally substituted by an oxygen atom;R₁₃ represents a straight or branched alkyl chain optionally containingone or more O atoms or a monocycloalkyl or polycycloalkyl groupoptionally containing one or more O atoms;R₁₄ and R₁₅ each independently represent a hydrogen atom, a straight orbranched alkyl chain optionally containing one or more O atoms or amonocycloalkyl or polycycloalkyl group optionally containing one or moreO atoms;R₁₆ represents a straight or branched alkyl chain optionally containingone or more O atoms, a monocycloalkyl or polycycloalkyl group optionallycontaining one or more O atoms, aryl, or aralkyl; andR₁₇ represents straight or branched alkyl chain optionally containingone or more O atoms, a monocycloalkyl or polycycloalkyl group optionallycontaining one or more O atoms, aryl, aralkyl, the group —Si(R₁₆)₂R₁₇,or the group —O—Si(R₁₆)₂R₁₇, the straight or branched alkyl chainoptionally containing one or more O atoms, monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms, aryl,and aralkyl being unsubstituted or substituted as above.

The present invention also relates to a photoresist compositioncomprising a polymer containing an acid labile group and a compound asdescribed above. Optionally, the photoresist composition can alsocontain one or more additional photoacid generators selected from (a) acompound having the formula (Ai)₂Xi1, where each Ai is as defined aboveand can be different and Xi1 is an anion of the formula Q-R₅₀₀—SO₃ ⁻,where Q is selected from ⁻O₃S and ⁻O₂C; and R₅₀₀ is a group selectedfrom linear or branched alkyl, cycloalkyl, aryl, or combinationsthereof, optionally containing a catenary S or N, where the alkyl,cycloalkyl, and aryl groups are unsubstituted or substituted by one ormore groups selected from the group consisting of halogen, unsubstitutedor substituted alkyl, unsubstituted or substituted C₁₋₈ perfluoroalkyl,hydroxyl, cyano, sulfate, and nitro; and (b) a compound having theformula AiXi2, where Ai is an organic onium cation as previously definedand Xi2 is an anion; and mixtures of (a) and (b) thereof. Examples ofthe Xi2 anion include CF₃SO₃ ⁻, CHF₂SO₃ ⁻, CH₃SO₃ ⁻, CCl₃SO₃ ⁻, C₂F₅SO₃⁻, C₂HF₄SO₃ ⁻, C₄F₉SO₃ ⁻, camphor sulfonate, perfluorooctane sulfonate,benzene sulfonate, pentafluorobenzene sulfonate, toluene sulfonate,perfluorotoluene sulfonate, (Rf1SO₂)₃C⁻ and (Rf1SO₂)₂N⁻, wherein eachRf1 is independently selected from the group consisting of highlyfluorinated or perfluorinated alkyl or fluorinated aryl radicals and maybe cyclic, when a combination of any two Rf1 groups are linked to form abridge, further, the Rf1 alkyl chains contain from 1-20 carbon atoms andmay be straight, branched, or cyclic, such that divalent oxygen,trivalent nitrogen or hexavalent sulfur may interrupt the skeletalchain, further when Rf1 contains a cyclic structure, such structure has5 or 6 ring members, optionally, 1 or 2 of which are heteroatoms, andRg-O-Rf2-SO₃ ⁻, where Rf2 is selected from the group consisting oflinear or branched (CF₂)_(j) where j is an integer from 4 to 10 andC₁-C₁₂ cycloperfluoroalkyl divalent radical which is optionallyperfluoroC₁₋₁₀alkyl substituted, Rg is selected from the groupconsisting of C₁-C₂₀ linear, branched, monocycloalkyl or polycycloalkyl,C₁-C₂₀ linear, branched, monocycloalkenyl or polycycloalkenyl, aryl, andaralkyl, the alkyl, alkenyl, aralkyl and aryl groups beingunsubstituted, substituted, optionally containing one or more catenaryoxygen atoms, partially fluorinated or perfluorinated. Examples of suchanions Xi2 include (C₂F₅SO₂)₂N⁻, (C₄F₉SO₂)₂N⁻, (C₈F₁₇SO₂)₃C⁻,(CF₃SO₂)₃C⁻, (CF₃SO₂)₂N⁻, (CF₃SO₂)₂(C₄F₉SO₂)C⁻, (C₂F₅SO₂)₃C⁻,(C₄F₉SO₂)₃C⁻, (CF₃SO₂)₂(C₂F₅SO₂)C⁻, (C₄F₉SO₂)(C₂F₅SO₂)₂C⁻,(CF₃SO₂)(C₄F₉SO₂)N⁻, [(CF₃)₂NC₂F₄SO₂]₂N⁻, (CF₃)₂NC₂F₄SO₂C⁻(SO₂CF₃)₂,(3,5-bis(CF₃)C₆H₃)SO₂N⁻SO₂CF₃, C₆F₅SO₂C⁻(SO₂CF₃)₂, C₆F₅SO₂N⁻SO₂CF₃,

CF₃CHFO(CF₂)₄SO₃ ⁻, CF₃CH₂O(CF₂)₄SO₃ ⁻, CH₃CH₂O(CF₂)₄SO₃ ⁻,CH₃CH₂CH₂O(CF₂)₄SO₃ ⁻, CH₃O(CF₂)₄SO₃ ⁻, C₂H₅O(CF₂)₄SO₃ ⁻, C₄H₉O(CF₂)₄SO₃⁻, C₆H₅CH₂O(CF₂)₄SO₃ ⁻, C₂H₅OCF₂CF(CF₃)SO₃ ⁻, CH₂═CHCH₂O(CF₂)₄SO₃ ⁻,CH₃OCF₂CF(CF₃)SO₃ ⁻, C₄H₉OCF₂CF(CF₃)SO₃ ⁻, C₈H₁₇O(CF₂)₂SO₃ ⁻, andC₄H₉O(CF₂)₂SO₃ ⁻. Other examples of suitable anions can be found in U.S.Pat. Nos. 6,841,333 and 5,874,616.

Examples of AiXi2 include bis(4-t-butylphenyl)iodoniumbis-perfluoroethane sulfonimide, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluorobutane sulfonate,triphenylsulfonium trifluromethane sulfonate, triphenylsulfoniumnonafluorobutane sulfonate, 4-(1-butoxyphenyl)diphenylsulfoniumbis-(perfluorobutanesulfonyl)imide, 4-(1-butoxyphenyl)diphenylsulfoniumbis-(perfluoroethanesulfonyl)imide,2,4,6-trimethylphenyldiphenylsulfoniumbis-(perfluorobutanesulfonyl)imide,2,4,6-trimethylphenyldiphenylsulfoniumbis-(perfluoroethanesulfonyl)imide, toluenediphenylsulfoniumbis-(perfluorobutanesulfonyl)imide, toluenediphenylsulfoniumbis-(perfluoroethanesulfonyl)imide,toluenediphenylsulfonium-(trifluoromethyl perfluorobutylsulfonyl)imide,tris-(tert-butylphenyl)sulfonium-(trifluoromethylperfluorobutylsulfonyl)imide, tris-(tert-butylphenyl)sulfoniumbis-(perfluorobutanesulfonyl)imide,tris-(tert-butylphenyl)sulfonium-bis-(trifluoromethanesulfonyl)imide,and the like as well as other photoacid generators known to thoseskilled in the art.

When used in combination, the ratio of the inventive photoacidgenerators to the additional photoacid generators ranges from about1:0.6 to about 1:1.3.

Processes for making coated substrates using the inventive photoacidgenerators as well as coated substrates are also provided for herein.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a compound of the formulaAiXi,where Ai is an organic onium cation; andXi is anion of the formula X—CF₂CF₂OCF₂CF₂—SO₃ ⁻, where X is selectedfrom halogen, alkyl, alkoxy and aryloxy;where Ai is selected from

andY—Arwhere Ar is selected from

naphthyl, or anthryl;Y is selected from

where R₁, R₂, R₃, R_(1A), R_(1B), R_(2A), R_(2B), R_(3A), R_(3B),R_(4A), R_(4B), R_(5A), and R_(5B) are each independently selected fromZ, hydrogen, OSO₂R₉, OR₂₀, straight or branched alkyl chain optionallycontaining one or more O atoms, monocycloalkyl or polycycloalkyl groupoptionally containing one or more O atoms, monocycloalkyl- orpolycycloalkylcarbonyl group, aryl, aralkyl, arylcarbonylmethyl group,alkoxyalkyl, alkoxycarbonylalkyl, alkylcarbonyl, monocycloalkyl- orpolycycloalkyloxycarbonylalkyl with the cycloalkyl ring optionallycontaining one or more O atoms, monocycloalkyl- orpolycycloalkyloxyalkyl with the cycloalkyl ring optionally containingone or more O atoms, straight or branched perfluoroalkyl,monocycloperfluoroalkyl or polycycloperfluoroalkyl, straight or branchedalkoxy chain, nitro, cyano, halogen, carboxyl, hydroxyl, sulfate,tresyl, or hydroxyl;R₆ and R₇ are each independently selected from straight or branchedalkyl chain optionally containing one or more O atoms, monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms,monocycloalkyl- or polycycloalkylcarbonyl group, aryl, aralkyl, straightor branched perfluoroalkyl, monocycloperfluoroalkyl orpolycycloperfluoroalkyl, arylcarbonylmethyl group, nitro, cyano, orhydroxyl or R₆ and R₇ together with the S atom to which they areattached form a 5-, 6-, or 7-membered saturated or unsaturated ringoptionally containing one or more O atoms;R₉ is selected from alkyl, fluoroalkyl, perfluoroalkyl, aryl,fluoroaryl, perfluoroaryl, monocycloalkyl or polycycloalkyl group withthe cycloalkyl ring optionally containing one or more O atoms,monocyclofluoroalkyl or polycyclofluoroalkyl group with the cycloalkylring optionally containing one or more O atoms, ormonocycloperfluoralkyl or polycycloperfluoroalkyl group with thecycloalkyl ring optionally containing one or more O atoms;R₂₀ is alkoxyalkyl, alkoxycarbonylalkyl, alkylcarbonyl, monocycloalkyl-or polycycloalkyloxycarbonylalkyl with the cycloalkyl ring optionallycontaining one or more O atoms, or monocycloalkyl- orpolycycloalkyloxyalkyl with the cycloalkyl ring optionally containingone or more O atoms;T is a direct bond, a divalent straight or branched alkyl groupoptionally containing one or more O atoms, divalent aryl group, divalentaralkyl group, or divalent monocycloalkyl or polycycloalkyl groupoptionally containing one or more O atoms;Z is —(V)_(j)—(C(X11)(X12))_(n)—O—C(═O)—R₈, where either (i) one of X11or X12 is straight or branched alkyl chain containing at least onefluorine atom and the other is hydrogen, halogen, or straight orbranched alkyl chain or (ii) both of X11 and X12 are straight orbranched alkyl chain containing at least one fluorine atom;V is a linkage group selected from a direct bond, a divalent straight orbranched alkyl group optionally containing one or more O atoms, divalentaryl group, divalent aralkyl group, or divalent monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms;X2 is hydrogen, halogen, or straight or branched alkyl chain optionallycontaining one or more O atoms;R₈ is a straight or branched alkyl chain optionally containing one ormore O atoms, a monocycloalkyl or polycycloalkyl group optionallycontaining one or more O atoms, or aryl;X3 is hydrogen, straight or branched alkyl chain, halogen, cyano, or—C(═O)—R₅₀ where R₅₀ is selected from straight or branched alkyl chainoptionally containing one or more O atoms or —O—R₅₁ where R₅₁ ishydrogen or straight or branched alkyl chain;each of i and k are independently 0 or a positive integer;j is 0 to 10;m is 0 to 10;and n is 0 to 10,the straight or branched alkyl chain optionally containing one or more Oatoms, straight or branched alkyl chain, straight or branched alkoxychain, monocycloalkyl or polycycloalkyl group optionally containing oneor more O atoms, monocycloalkyl- or polycycloalkylcarbonyl group,alkoxyalkyl, alkoxycarbonylalkyl, alkylcarbonyl, monocycloalkyl- orpolycycloalkyloxycarbonylalkyl with the cycloalkyl ring optionallycontaining one or more O atoms, monocycloalkyl- orpolycycloalkyloxyalkyl with the cycloalkyl ring optionally containingone or more O atoms, aralkyl, aryl, naphthyl, anthryl, 5-, 6-, or7-membered saturated or unsaturated ring optionally containing one ormore O atoms, or arylcarbonylmethyl group being unsubstituted orsubstituted by one or more groups selected from the group consisting ofZ, halogen, alkyl, C₁₋₈ perfluoroalkyl, monocycloalkyl orpolycycloalkyl, OR₂₀, alkoxy, C₃₋₂₀ cyclic alkoxy, dialkylamino,dicyclic dialkylamino, hydroxyl, cyano, nitro, tresyl, oxo, aryl,aralkyl, oxygen atom, CF₃SO₃, aryloxy, arylthio, and groups of formulae(II) to (VI):

wherein R₁₀ and R₁₁ each independently represent a hydrogen atom, astraight or branched alkyl chain optionally containing one or more Oatoms, or a monocycloalkyl or polycycloalkyl group optionally containingone or more O atoms, or R₁₀ and R₁₁ together can represent an alkylenegroup to form a five- or six-membered ring;R₁₂ represents a straight or branched alkyl chain optionally containingone or more O atoms, a monocycloalkyl or polycycloalkyl group optionallycontaining one or more O atoms, or aralkyl, or R₁₀ and R₁₂ togetherrepresent an alkylene group which forms a five- or six-membered ringtogether with the interposing —C—O— group, the carbon atom in the ringbeing optionally substituted by an oxygen atom;R₁₃ represents a straight or branched alkyl chain optionally containingone or more O atoms or a monocycloalkyl or polycycloalkyl groupoptionally containing one or more O atoms;R₁₄ and R₁₅ each independently represent a hydrogen atom, a straight orbranched alkyl chain optionally containing one or more O atoms or amonocycloalkyl or polycycloalkyl group optionally containing one or moreO atoms;R₁₆ represents a straight or branched alkyl chain optionally containingone or more O atoms, a monocycloalkyl or polycycloalkyl group optionallycontaining one or more O atoms, aryl, or aralkyl; andR₁₇ represents straight or branched alkyl chain optionally containingone or more O atoms, a monocycloalkyl or polycycloalkyl group optionallycontaining one or more O atoms, aryl, aralkyl, the group —Si(R₁₆)₂R₁₇,or the group —O—Si(R₁₆)₂R₁₇, the straight or branched alkyl chainoptionally containing one or more O atoms, monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms, aryl,and aralkyl being unsubstituted or substituted as above.

The present invention also relates to a photoresist compositioncomprising a polymer containing an acid labile group and a compound asdescribed above. Optionally, the photoresist composition can alsocontain one or more additional photoacid generators selected from (a) acompound having the formula (Ai)₂Xi1, where each Ai is as defined aboveand can be different and Xi1 is an anion of the formula Q-R₅₀₀—SO₃ ⁻,where Q is selected from ⁻O₃S and ⁻O₂C; and R₅₀₀ is a group selectedfrom linear or branched alkyl, cycloalkyl, aryl, or combinationsthereof, optionally containing a catenary S or N, where the alkyl,cycloalkyl, and aryl groups are unsubstituted or substituted by one ormore groups selected from the group consisting of halogen, unsubstitutedor substituted alkyl, unsubstituted or substituted C₁₋₈ perfluoroalkyl,hydroxyl, cyano, sulfate, and nitro; and (b) a compound having theformula AiXi2, where Ai is an organic onium cation as previously definedand Xi2 is an anion; and mixtures of (a) and (b) thereof. Examples ofthe Xi2 anion include CF₃SO₃ ⁻, CHF₂SO₃ ⁻, CH₃SO₃ ⁻, CCl₃SO₃ ⁻, C₂F₅SO₃⁻, C₂HF₄SO₃ ⁻, C₄F₉SO₃ ⁻, camphor sulfonate, perfluorooctane sulfonate,benzene sulfonate, pentafluorobenzene sulfonate, toluene sulfonate,perfluorotoluene sulfonate, (Rf1SO₂)₃C⁻ and (Rf1SO₂)₂N⁻, wherein eachRf1 is independently selected from the group consisting of highlyfluorinated or perfluorinated alkyl or fluorinated aryl radicals and maybe cyclic, when a combination of any two Rf1 groups are linked to form abridge, further, the Rf1 alkyl chains contain from 1-20 carbon atoms andmay be straight, branched, or cyclic, such that divalent oxygen,trivalent nitrogen or hexavalent sulfur may interrupt the skeletalchain, further when Rf1 contains a cyclic structure, such structure has5 or 6 ring members, optionally, 1 or 2 of which are heteroatoms, andRg-O-Rf2-SO₃ ⁻, where Rf2 is selected from the group consisting oflinear or branched (CF₂)_(j) where j is an integer from 4 to 10 andC₁-C₁₂ cycloperfluoroalkyl divalent radical which is optionallyperfluoroC₁₋₁₀alkyl substituted, Rg is selected from the groupconsisting of C₁-C₂₀ linear, branched, monocycloalkyl or polycycloalkyl,C₁-C₂₀ linear, branched, monocycloalkenyl or polycycloalkenyl, aryl, andaralkyl, the alkyl, alkenyl, aralkyl and aryl groups beingunsubstituted, substituted, optionally containing one or more catenaryoxygen atoms, partially fluorinated or perfluorinated. Examples of suchanions Xi2 include (C₂F₅SO₂)₂N⁻, (C₄F₉SO₂)₂N⁻, (C₈F₁₇SO₂)₃C⁻,(CF₃SO₂)₃C⁻, (CF₃SO₂)₂N⁻, (CF₃SO₂)₂(C₄F₉SO₂)C⁻, (C₂F₅SO₂)₃C⁻,(C₄F₉SO₂)₃C⁻, (CF₃SO₂)₂(C₂F₅SO₂)C⁻, (C₄F₉SO₂)(C₂F₅SO₂)₂C⁻,(CF₃SO₂)(C₄F₉SO₂)N⁻, [(CF₃)₂NC₂F₄SO₂]₂N⁻, (CF₃)₂NC₂F₄SO₂C⁻(SO₂CF₃)₂,(3,5-bis(CF₃)C₆H₃)SO₂N⁻SO₂CF₃, C₆F₅SO₂C⁻(SO₂CF₃)₂, C₆F₅SO₂N⁻SO₂CF₃,

CF₃CHFO(CF₂)₄SO₃ ⁻, CF₃CH₂O(CF₂)₄SO₃ ⁻, CH₃CH₂O(CF₂)₄SO₃ ⁻,CH₃CH₂CH₂O(CF₂)₄SO₃ ⁻, CH₃O(CF₂)₄SO₃ ⁻, C₂H₅O(CF₂)₄SO₃ ⁻, C₄H₉O(CF₂)₄SO₃⁻, C₆H₅CH₂O(CF₂)₄SO₃ ⁻, C₂H₅OCF₂CF(CF₃)SO₃ ⁻, CH₂═CHCH₂O(CF₂)₄SO₃ ⁻,CH₃OCF₂CF(CF₃)SO₃ ⁻, C₄H₉OCF₂CF(CF₃)SO₃ ⁻, C₈H₁₇O(CF₂)₂SO₃ ⁻, andC₄H₉O(CF₂)₂SO₃ ⁻. Other examples of suitable anions can be found in U.S.Pat. Nos. 6,841,333 and 5,874,616.

Examples of AiXi2 include bis(4-t-butylphenyl)iodoniumbis-perfluoroethane sulfonimide, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluorobutane sulfonate,triphenylsulfonium trifluromethane sulfonate, triphenylsulfoniumnonafluorobutane sulfonate, 4-(1-butoxyphenyl)diphenylsulfoniumbis-(perfluorobutanesulfonyl)imide, 4-(1-butoxyphenyl)diphenylsulfoniumbis-(perfluoroethanesulfonyl)imide,2,4,6-trimethylphenyldiphenylsulfoniumbis-(perfluorobutanesulfonyl)imide,2,4,6-trimethylphenyldiphenylsulfoniumbis-(perfluoroethanesulfonyl)imide, toluenediphenylsulfoniumbis-(perfluorobutanesulfonyl)imide, toluenediphenylsulfoniumbis-(perfluoroethanesulfonyl)imide,toluenediphenylsulfonium-(trifluoromethyl perfluorobutylsulfonyl)imide,tris-(tert-butylphenyl)sulfonium-(trifluoromethylperfluorobutylsulfonyl)imide, tris-(tert-butylphenyl)sulfoniumbis-(perfluorobutanesulfonyl)imide,tris-(tert-butylphenyl)sulfonium-bis-(trifluoromethanesulfonyl)imide,and the like as well as other photoacid generators known to thoseskilled in the art.

When used in combination, the ratio of the inventive photoacidgenerators to the additional photoacid generators ranges from about1:0.6 to about 1:1.3.

Processes for making coated substrates using the inventive photoacidgenerators as well as coated substrates are also provided for herein.

The term alkyl as used herein means a straight or branched chainhydrocarbon. Representative examples of alkyl include, but are notlimited to, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl,iso-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl,3-methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl,n-octyl, n-nonyl, and n-decyl.

Alkylene refers to divalent alkyl radicals, which can be linear orbranched, such as, for example, methylene, ethylene, propylene, butyleneor the like.

By the term aryl is meant a radical derived from an aromatic hydrocarbonby the elimination of one atom of hydrogen and can be substituted orunsubstituted. The aromatic hydrocarbon can be mononuclear orpolynuclear. Examples of aryl of the mononuclear type include phenyl,tolyl, xylyl, mesityl, cumenyl, and the like. Examples of aryl of thepolynuclear type include naphthyl, anthryl, phenanthryl, and the like.The aryl group can be unsubstituted or substituted as provided forhereinabove.

The term alkoxy refers to a group of alkyl-O—, where alkyl is definedherein. Representative examples of alkoxy include, but are not limitedto, methoxy, ethoxy, propoxy, 2-propoxy, butoxy, tert-butoxy, pentyloxy,and hexyloxy.

The term aryloxy refers to a group of aryl-O—, where aryl is definedherein.

By the term aralkyl is meant an alkyl group containing an aryl group. Itis a hydrocarbon group having both aromatic and aliphatic structures,that is, a hydrocarbon group in which a lower alkyl hydrogen atom issubstituted by a mononuclear or polynuclear aryl group. Examples ofaralkyl groups include, without limitation, benzyl, 2-phenyl-ethyl,3-phenyl-propyl, 4-phenyl-butyl, 5-phenyl-pentyl, 4-phenylcyclohexyl,4-benzylcyclohexyl, 4-phenylcyclohexylmethyl, 4-benzylcyclohexylmethyl,naphthylmethyl, and the like.

The term monocycloalkyl as used herein, refers to an optionallysubstituted, saturated or partially unsaturated monocycloalkyl ringsystem, where if the ring is partially unsaturated, it is then amonocycloalkenyl group. The term polycycloalkyl as used herein refers toan optionally substituted, saturated or partially unsaturatedpolycycloalkyl ring system containing two or more rings, where if thering is partially unsaturated, it is then a polycycloalkenyl group.Examples of monocycloalkyl or polycycloalkyl groups optionallycontaining one or more O atoms are well know to those skilled in the artand include, for example, cyclopropyl, cyclobutyl, cyclopentyl,cycloheptyl, cyclohexyl, 2-methyl-2-norbornyl, 2-ethyl-2-norbornyl,2-methyl-2-isobornyl, 2-ethyl-2-isobornyl, 2-methyl-2-adamantyl,2-ethyl-2-adamantyl, 1-adamantyl-1-methylethyl, adamantyl,tricyclodecyl, 3-oxatricyclo[4.2.1.0^(2,5)]nonyl, tetracyclododecanyl,tetracyclo[5.2.2.0.0]undecanyl, bornyl, isobornyl norbornyl lactone,adamantyl lactone and the like.

The term alkoxycarbonylalkyl embraces alkyl radicals substituted with analkoxycarbonyl radical as defined herein. Examples ofalkoxycarbonylalkyl radicals include methoxycarbonylmethyl[CH₃O—C(═O)—CH₂—], ethoxycarbonylmethyl [CH₃CH₂O—C(═O)—CH₂—],methoxycarbonylethyl [CH₃O—C(═O)—CH₂CH₂—], and ethoxycarbonylethyl[CH₃CH₂O—C(═O)—CH₂CH₂—].

The term alkylcarbonyl as used herein means an alkyl group, as definedherein, appended to the parent molecular moiety through a carbonylgroup, as defined herein, which can be generically represented asalkyl-C(O)—. Representative examples of alkylcarbonyl include, but arenot limited to acetyl (methyl carbonyl), butyryl(propylcarbonyl),octanoyl(heptylcarbonyl), dodecanoyl (undecylcarbonyl), and the like.

Alkoxycarbonyl means alkyl-O—C(O)—, wherein alkyl is as previouslydescribed. Non-limiting examples include methoxycarbonyl [CH₃O—C(O)—]and the ethoxycarbonyl [CH₃CH₂O—C(O)—], benzyloxycarbonyl[C₆H₅CH₂O—C(O)—] and the like.

Alkoxyalkyl means that a terminal alkyl group is linked through an etheroxygen atom to an alkyl moiety, which can be generically represented asalkyl-O-alkyl wherein the alkyl groups can be linear or branched.Examples of alkoxyalkyl include, but are not limited to, methoxypropyl,methoxybutyl, ethoxypropyl, methoxymethyl

Monocycloalkyl- or polycycloalkyloxycarbonylalkyl means that a terminalmonocycloalkyl or polycycloalkyl group is linked through —O—C(═O)— to analkyl moiety, generically represented as monocycloalkyl- orpolycycloalkyl-O—C(═O)-alkyl.

Monocycloalkyl- or polycycloalkyloxyalkyl means that a terminalmonocycloalkyl or polycycloalkyl group is linked through an ether oxygenatom to an alkyl moiety, which can be generically represented asmonocycloalkyl- or polycycloalkyl-O-alkyl.

Monocyclofluoroalkyl- or polycyclofluoroalkyl means a monocyclalkyl- orpolycycloalkyl group substituted with one or more fluorine atoms.

Polymers useful in the photoresist compositions include those that haveacid labile groups that make the polymer insoluble in aqueous alkalinesolution, but such a polymer in the presence of an acid catalyticallydeprotects the polymer, wherein the polymer then becomes soluble in anaqueous alkaline solution. The polymers preferably are transparent below200 nm, and are essentially non-aromatic, and preferably are acrylatesand/or cycloolefin polymers. Such polymers are, for example, but notlimited to, those described in U.S. Pat. Nos. 5,843,624, 5,879,857, WO97/33,198, EP 789,278 and GB 2,332,679. Nonaromatic polymers that arepreferred for irradiation below 200 nm are substituted acrylates,cycloolefins, substituted polyethylenes, etc. Aromatic polymers based onpolyhydroxystyrene and its copolymers may also be used, especially for248 nm exposure.

Polymers based on acrylates are generally based on poly(meth)acrylateswith at least one unit containing pendant alicyclic groups, and with theacid labile group being pendant from the polymer backbone and/or fromthe alicyclic group. Examples of pendant alicyclic groups, may beadamantyl, tricyclodecyl, isobornyl, menthyl and their derivatives.Other pendant groups may also be incorporated into the polymer, such asmevalonic lactone, gamma butyrolactone, alkyloxyalkyl, etc. Examples ofstructures for the alicyclic group include:

The type of monomers and their ratios incorporated into the polymer areoptimized to give the best lithographic performance. Such polymers aredescribed in R. R. Dammel et al., Advances in Resist Technology andProcessing, SPIE, Vol. 3333, p 144, (1998). Examples of these polymersinclude poly(2-methyl-2-adamantyl methacrylate-co-mevalonic lactonemethacrylate), poly(carboxy-tetracyclododecylmethacrylate-co-tetrahydropyranylcarboxytetracyclododecyl methacrylate),poly(tricyclodecylacrylate-co-tetrahydropyranylmethacrylate-co-methacrylicacid),poly(3-oxocyclohexyl methacrylate-co-adamantylmethacrylate).

Polymers synthesized from cycloolefins, with norbornene andtetracyclododecene derivatives, may be polymerized by ring-openingmetathesis, free-radical polymerization or using metal organiccatalysts. Cycloolefin derivatives may also be copolymerized with cyclicanhydrides or with maleimide or its derivatives. Examples of cyclicanhydrides are maleic anhydride (MA) and itaconic anhydride. Thecycloolefin is incorporated into the backbone of the polymer and may beany substituted or unsubstituted multicyclic hydrocarbon containing anunsaturated bond. The monomer can have acid labile groups attached. Thepolymer may be synthesized from one or more cycloolefin monomers havingan unsaturated bond. The cycloolefin monomers may be substituted orunsubstituted norbornene, or tetracyclododecane. The substituents on thecycloolefin may be aliphatic or cycloaliphatic alkyls, esters, acids,hydroxyl, nitrile or alkyl derivatives. Examples of cycloolefinmonomers, without limitation, include:

Other cycloolefin monomers which may also be used in synthesizing thepolymer are:

Such polymers are described in the following reference and incorporatedherein, M-D. Rahman et al, Advances in Resist Technology and Processing,SPIE, Vol. 3678, p 1193, (1999). Examples of these polymers includepoly((t-butyl-5-norbornene-2-carboxylate-co-2-hydroxyethyl-5-norbornene-2-carboxylate-co-5-norbornene-2-carboxylicacid-co-maleic anhydride),poly(t-butyl-5-norbornene-2-carboxylate-co-isobornyl-5-norbornene-2-carboxylate-co-2-hydroxyethyl-5-norbornene-2-carboxylate-co-5-norbornene-2-carboxylicacid-co-maleic anhydride),poly(tetracyclododecene-5-carboxylate-co-maleic an hydride),poly(t-butyl-5-norbornene-2-carboxylate-co-maleicanhydride-co-2-methyladamantyl methacrylate-co-2-mevalonic lactonemethacrylate), poly(2-methyladamantyl methacrylate-co-2-mevaloniclactone methacylate) and the like.

Polymers containing mixtures of (meth)acrylate monomers, cycloolefinicmonomers and cyclic anhydrides, where such monomers are described above,may also be combined into a hybrid polymer. Examples of cycloolefinmonomers include those selected from t-butyl norbornene carboxylate(BNC), hydroxyethyl norbornene carboxylate (HNC), norbornene carboxylicacid (NC),t-butyltetracyclo[4.4.0.1.^(2,6)1.^(7,10)]dodec-8-ene-3-carboxylate, andt-butoxy carbonylmethyltetracyclo[4.4.0.1.^(2,6)1.^(7,10)]dodec-8-ene-3-carboxylate. In someinstances, preferred examples of cycloolefins include t-butyl norbornenecarboxylate (BNC), hydroxyethyl norbornene carboxylate (HNC), andnorbornene carboxylic acid (NC). Examples of (meth)acrylate monomersinclude those selected from mevalonic lactone methacrylate (MLMA),2-methyl-2-adamantyl methacrylate (MAdMA), 2-adamantyl methacrylate(AdMA), 2-methyl-2-adamantyl acrylate (MAdA), 2-ethyl-2-adamantylmethacrylate (EAdMA), 3,5-dimethyl-7-hydroxy adamantyl methacrylate(DMHAdMA), adamantyl methyloxy methyl methacrylate (AdOMMA),isoadamantyl methacrylate, hydroxy-1-methacryloxyadamatane (HAdMA; forexample, hydroxy at the 3-position), hydroxy-1-adamantyl acrylate (HADA;for example, hydroxy at the 3-position), ethylcyclopentylacrylate(ECPA), ethylcyclopentylmethacrylate (ECPMA),tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate (TCDMA),3,5-dihydroxy-1-methacryloxyadamantane (DHAdMA),β-methacryloxy-γ-butyrolactone, α- or β-gamma-butyrolactone methacrylate(either α- or β-GBLMA), 5-methacryloyloxy-2,6-norbornanecarbolactone(MNBL), 5-acryloyloxy-2,6-norbornanecarbolactone (ANBL), isobutylmethacrylate (IBMA), α-gamma-butyrolactone acrylate (α-GBLA),spirolactone (meth)acrylate, oxytricyclodecane (meth)acrylate,adamantane lactone (meth)acrylate, and α-methacryloxy-γ-butyrolactone,among others. Examples of polymers formed with these monomers includepoly(2-methyl-2-adamantyl methacrylate-co-2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-α-gamma-butyrolactonemethacrylate); poly(2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate); poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate); poly(t-butyl norbornene carboxylate-co-maleicanhydride-co-2-methyl-2-adamantyl methacrylate-co-β-gamma-butyrolactonemethacrylate-co-methacryloyloxy norbornene methacrylate);poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-β-gamma-butyrolactone methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-methyl-2-adamantylmethacrylate-co-3,5-dihydroxy-1-methacryloxyadamantane-co-α-gamma-butyrolactonemethacrylate); poly(2-methyl-2-adamantylmethacrylate-co-3,5-dimethyl-7-hydroxy adamantylmethacrylate-co-α-gamma-butyrolactone methacrylate);poly(2-methyl-2-adamantylacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-α-gamma-butyrolactonemethacrylate); poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-methyl-2-adamantyl methacrylate-co-β-gamma-butyrolactonemethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-ethylcyclopentylacrylate);poly(2-methyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactone methacrylate);poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-α-gamma-butyrolactonemethacrylate-co-2-ethyl-2-adamantyl methacrylate);poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-methyl-2-adamantyl methacrylate-co-2-ethyl-2-adamantylmethacrylate-co-β-gamma-butyrolactonemethacrylate-co-3-hydroxy-1-methacryloxyadamantane);poly(2-methyl-2-adamantyl methacrylate-co-2-ethyl-2-adamantylmethacrylate-co-α-gamma-butyrolactonemethacrylate-co-3-hydroxy-1-methacryloxyadamantane);poly(2-methyl-2-adamantyl methacrylate-co-methacryloyloxy norbornenemethacrylate-co-β-gamma-butyrolactone methacrylate);poly(ethylcyclopentylmethacrylate-co-2-ethyl-2-adamantylmethacrylate-co-α-gamma-butyrolactone acrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-isobutyl methacrylate-co-α-gamma-butyrolactone acrylate);poly(2-methyl-2-adamantyl methacrylate-co-β-gamma-butyrolactonemethacrylate-co-3-hydroxy-1-adamantylacrylate-co-tricyclo[5,2,1,02,6]deca-8-yl methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactone acrylate); poly(2-methyl-2-adamantylmethacrylate-co-β gamma-butyrolactone methacrylate-co-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamatane);poly(2-methyl-2-adamantyl methacrylate-co-methacryloyloxy norbornenemethacrylate-co-β-gamma-butyrolactone methacrylate-co-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamatane);poly(2-methyl-2-adamantyl methacrylate-co-methacryloyloxy norbornenemethacrylate-co-tricyclo[5,2,1,02,6]deca-8-ylmethacrylate-co-3-hydroxy-1-methacryloxyadamatane-co-α-gamma-butyrolactonemethacrylate); poly(2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-adamantylacrylate-co-tricyclo[5,2,1,02,6]deca-8-ylmethacrylate-co-α-gamma-butyrolactone methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactone acrylate); poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamatane-co-α-gamma-butyrolactonemethacrylate-co-2-ethyl-2-adamantyl-co-methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactone methacrylate);poly(2-methyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-5-acryloyloxy-2,6-norbornanecarbolactone);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactone methacrylate-co-α-gamma-butyrolactoneacrylate); poly(2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-adamantyl acrylate-co-α-gamma-butyrolactonemethacrylate-co-2-adamantyl methacrylate); and poly(2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-adamantyl acrylate-co-α-gamma-butyrolactoneacrylate-co-tricyclo[5,2,1,02,6]deca-8-yl methacrylate).

Other examples of suitable polymers include those described in U.S. Pat.Nos. 6,610,465, 6,120,977, 6,136,504, 6,013,416, 5,985,522, 5,843,624,5,693,453, 4,491,628, WO 00/25178, WO 00/67072, JP 2000-275845, JP2000-137327, and JP 09-73173 which are incorporated herein by reference.Blends of one or more photoresist resins may be used. Standard syntheticmethods are typically employed to make the various types of suitablepolymers. Procedures or references to suitable standard procedures(e.g., free radical polymerization) can be found in the aforementioneddocuments.

The cycloolefin and the cyclic anhydride monomer are believed to form analternating polymeric structure, and the amount of the (meth)acrylatemonomer incorporated into the polymer can be varied to give the optimallithographic properties. The percentage of the (meth)acrylate monomerrelative to the cycloolefin/anhydride monomers within the polymer rangesfrom about 95 mole % to about 5 mole %, further ranging from about 75mole % to about 25 mole %, and also further ranging from about 55 mole %to about 45 mole %.

Fluorinated non-phenolic polymers, useful for 157 nm exposure, alsoexhibit line edge roughness and can benefit from the use of the novelmixture of photoactive compounds described in the present invention.Such polymers are described in WO 00/17712 and WO 00/67072 andincorporated herein by reference. Example of one such polymer ispoly(tetrafluoroethylene-co-norbornene-co-5-hexafluoroisopropanol-substituted2-norbornene.

Polymers synthesized from cycloolefins and cyano containing ethylenicmonomers are described in the U.S. Pat. No. 6,686,429, the contents ofwhich are hereby incorporated herein by reference, may also be used.

The molecular weight of the polymers is optimized based on the type ofchemistry used and on the lithographic performance desired. Typically,the weight average molecular weight is in the range of 3,000 to 30,000and the polydispersity is in the range 1.1 to 5, preferably 1.5 to 2.5.

Other polymers of interest include those found and described in U.S.patent application Ser. No. 10/371,262, filed Feb. 21, 2003, now filedas U.S. patent application Ser. No. 10/658,840, filed Dec. 17, 2003 (andpublished now as US patent application publication no. 2004/0166433, thecontents of which are incorporated herein by reference. Still otherpolymers, such as those disclosed in U.S. patent application Ser. No.10/440,452, filed May 16, 2003 titled “Photoresist Composition for DeepUV and Process Thereof”, the contents of which are hereby incorporatedherein by reference, may also be used.

The solid components of the present invention are dissolved in anorganic solvent. The amount of solids in the solvent or mixture ofsolvents ranges from about 1 weight % to about 50 weight %. The polymermay be in the range of 5 weight % to 90 weight % of the solids and thephotoacid generator may be in the range of 1 weight % to about 50 weight% of the solids. Suitable solvents for such photoresists may include forexample ketones such as acetone, methyl ethyl ketone, methyl isobutylketone, cyclohexanone, isophorone, methyl isoamyl ketone, 2-heptanone4-hydroxy, and 4-methyl 2-pentanone; C₁ to C₁₀ aliphatic alcohols suchas methanol, ethanol, and propanol; aromatic group containing-alcoholssuch as benzyl alcohol; cyclic carbonates such as ethylene carbonate andpropylene carbonate; aliphatic or aromatic hydrocarbons (for example,hexane, toluene, xylene, etc and the like); cyclic ethers, such asdioxane and tetrahydrofuran; ethylene glycol; propylene glycol; hexyleneglycol; ethylene glycol monoalkylethers such as ethylene glycolmonomethylether, ethylene glycol monoethylether; ethylene glycolalkylether acetates such as methylcellosolve acetate and ethylcellosolveacetate; ethylene glycol dialkylethers such as ethylene glycoldimethylether, ethylene glycol diethylether, ethylene glycolmethylethylether, diethylene glycol monoalkylethers such as diethyleneglycol monomethylether, diethylene glycol monoethylether, and diethyleneglycol dimethylether; propylene glycol monoalkylethers such as propyleneglycol methylether, propylene glycol ethylether, propylene glycolpropylether, and propylene glycol butylether; propylene glycolalkyletheracetates such as propylene glycol methylether acetate,propylene glycol ethylether acetate, propylene glycol propyletheracetate, and propylene glycol butylether acetate; propylene glycolalkyletherpropionates such as propylene glycol methyletherpropionate,propylene glycol ethyletherpropionate, propylene glycolpropyletherpropionate, and propylene glycol butyletherpropionate;2-methoxyethyl ether (diglyme); solvents that have both ether andhydroxy moieties such as methoxy butanol, ethoxy butanol, methoxypropanol, and ethoxy propanol; esters such as methyl acetate, ethylacetate, propyl acetate, and butyl acetate methyl-pyruvate, ethylpyruvate; ethyl 2-hydroxy propionate, methyl 2-hydroxy 2-methylpropionate, ethyl 2-hydroxy 2-methyl propionate, methyl hydroxy acetate,ethyl hydroxy acetate, butyl hydroxy acetate, methyl lactate, ethyllactate, propyl lactate, butyl lactate, methyl 3-hydroxy propionate,ethyl 3-hydroxy propionate, propyl 3-hydroxy propionate, butyl 3-hydroxypropionate, methyl 2-hydroxy 3-methyl butanoic acid, methyl methoxyacetate, ethyl methoxy acetate, propyl methoxy acetate, butyl methoxyacetate, methyl ethoxy acetate, ethyl ethoxy acetate, propyl ethoxyacetate, butyl ethoxy acetate, methyl propoxy acetate, ethyl propoxyacetate, propyl propoxy acetate, butyl propoxy acetate, methyl butoxyacetate, ethyl butoxy acetate, propyl butoxy acetate, butyl butoxyacetate, methyl 2-methoxy propionate, ethyl 2-methoxy propionate, propyl2-methoxy propionate, butyl 2-methoxy propionate, methyl2-ethoxypropionate, ethyl 2-ethoxypropionate, propyl 2-ethoxypropionate,butyl 2-ethoxypropionate, methyl 2-butoxypropionate, ethyl2-butoxypropionate, propyl 2-butoxypropionate, butyl 2-butoxypropionate,methyl 3-methoxypropionate, ethyl 3-methoxypropionate, propyl3-methoxypropionate, butyl 3-methoxypropionate, methyl3-ethoxypropionate, ethyl 3-ethoxypropionate, propyl 3-ethoxypropionate,butyl 3-ethoxypropionate, methyl 3-propoxypropionate, ethyl3-propoxypropionate, propyl 3-propoxypropionate, butyl3-propoxypropionate, methyl 3-butoxypropionate, ethyl3-butoxypropionate, propyl 3-butoxypropionate, and butyl3-butoxypropionate; oxyisobutyric acid esters, for example,methyl-2-hydroxyisobutyrate, methyl α-methoxyisobutyrate, ethylmethoxyisobutyrate, methyl α-ethoxyisobutyrate, ethylα-ethoxyisobutyrate, methyl β-methoxyisobutyrate, ethylβ-methoxyisobutyrate, methyl β-ethoxyisobutyrate, ethylβ-ethoxyisobutyrate, methyl β-isopropoxyisobutyrate, ethylβ-isopropoxyisobutyrate, isopropyl β-isopropoxyisobutyrate, butylβ-isopropoxyisobutyrate, methyl β-butoxyisobutyrate, ethylβ-butoxyisobutyrate, butyl β-butoxyisobutyrate, methylα-hydroxyisobutyrate, ethyl α-hydroxyisobutyrate, isopropylα-hydroxyisobutyrate, and butyl α-hydroxyisobutyrate; solvents that haveboth ether and hydroxy moieties such as methoxy butanol, ethoxy butanol,methoxy propanol, and ethoxy propanol; and other solvents such asdibasic esters, and gamma-butyrolactone; a ketone ether derivative suchas diacetone alcohol methyl ether; a ketone alcohol derivative such asacetol or diacetone alcohol; lactones such as butyrolactone; an amidederivative such as dimethylacetamide or dimethylformamide, anisole, andmixtures thereof.

Various other additives such as colorants, non-actinic dyes,anti-striation agents, plasticizers, adhesion promoters, dissolutioninhibitors, coating aids, photospeed enhancers, additional photoacidgenerators, and solubility enhancers (for example, certain small levelsof solvents not used as part of the main solvent (examples of whichinclude glycol ethers and glycol ether acetates, valerolactone, ketones,lactones, and the like), and surfactants may be added to the photoresistcomposition before the solution is coated onto a substrate. Surfactantsthat improve film thickness uniformity, such as fluorinated surfactants,can be added to the photoresist solution. A sensitizer that transfersenergy from a particular range of wavelengths to a different exposurewavelength may also be added to the photoresist composition. Often basesare also added to the photoresist to prevent t-tops or bridging at thesurface of the photoresist image. Examples of bases are amines, ammoniumhydroxide, and photosensitive bases. Particularly preferred bases aretrioctylamine, diethanolamine and tetrabutylammonium hydroxide.

The prepared photoresist composition solution can be applied to asubstrate by any conventional method used in the photoresist art,including dipping, spraying, and spin coating. When spin coating, forexample, the photoresist solution can be adjusted with respect to thepercentage of solids content, in order to provide coating of the desiredthickness, given the type of spinning equipment utilized and the amountof time allowed for the spinning process. Suitable substrates includesilicon, aluminum, polymeric resins, silicon dioxide, doped silicondioxide, silicon nitride, tantalum, copper, polysilicon, ceramics,aluminum/copper mixtures; gallium arsenide and other such Group III/Vcompounds. The photoresist may also be coated over antireflectivecoatings.

The photoresist coatings produced by the described procedure areparticularly suitable for application to silicon/silicon dioxide wafers,such as are utilized in the production of microprocessors and otherminiaturized integrated circuit components. An aluminum/aluminum oxidewafer can also be used. The substrate may also comprise variouspolymeric resins, especially transparent polymers such as polyesters.

The photoresist composition solution is then coated onto the substrate,and the substrate is treated (baked) at a temperature from about 70° C.to about 150° C. for from about 30 seconds to about 180 seconds on a hotplate or for from about 15 to about 90 minutes in a convection oven.This temperature treatment is selected in order to reduce theconcentration of residual solvents in the photoresist, while not causingsubstantial thermal degradation of the solid components. In general, onedesires to minimize the concentration of solvents and this firsttemperature. Treatment (baking) is conducted until substantially all ofthe solvents have evaporated and a thin coating of photoresistcomposition, on the order of half a micron (micrometer) in thickness,remains on the substrate. In a preferred embodiment the temperature isfrom about 95° C. to about 120° C. The treatment is conducted until therate of change of solvent removal becomes relatively insignificant. Thefilm thickness, temperature and time selection depends on thephotoresist properties desired by the user, as well as the equipmentused and commercially desired coating times. The coated substrate canthen be imagewise exposed to actinic radiation, e.g., ultravioletradiation, at a wavelength of from about 100 nm (nanometers) to about300 nm, x-ray, electron beam, ion beam or laser radiation, in anydesired pattern, produced by use of suitable masks, negatives, stencils,templates, etc.

The photoresist is then subjected to a post exposure second baking orheat treatment before development. The heating temperatures may rangefrom about 90° C. to about 150° C., more preferably from about 100° C.to about 130° C. The heating may be conducted for from about 30 secondsto about 2 minutes, more preferably from about 60 seconds to about 90seconds on a hot plate or about 30 to about 45 minutes by convectionoven.

The exposed photoresist-coated substrates are developed to remove theimage-wise exposed areas by immersion in a developing solution ordeveloped by spray development process. The solution is preferablyagitated, for example, by nitrogen burst agitation. The substrates areallowed to remain in the developer until all, or substantially all, ofthe photoresist coating has dissolved from the exposed areas. Developersinclude aqueous solutions of ammonium or alkali metal hydroxides. Onepreferred developer is an aqueous solution of tetramethyl ammoniumhydroxide. After removal of the coated wafers from the developingsolution, one may conduct an optional post-development heat treatment orbake to increase the coating's adhesion and chemical resistance toetching conditions and other substances. The post-development heattreatment can comprise the oven baking of the coating and substratebelow the coating's softening point or UV hardening process. Inindustrial applications, particularly in the manufacture ofmicrocircuitry units on silicon/silicon dioxide-type substrates, thedeveloped substrates may be treated with a buffered, hydrofluoric acidbase etching solution or dry etching. Prior to dry etching thephotoresist may be treated to electron beam curing in order to increasethe dry-etch resistance of the photoresist.

The invention further provides a method for producing a semiconductordevice by producing a photo-image on a substrate by coating a suitablesubstrate with a photoresist composition. The subject process comprisescoating a suitable substrate with a photoresist composition and heattreating the coated substrate until substantially all of the photoresistsolvent is removed; image-wise exposing the composition and removing theimage-wise exposed areas of such composition with a suitable developer.

The following examples provide illustrations of the methods of producingand utilizing the present invention. These examples are not intended,however, to limit or restrict the scope of the invention in any way andshould not be construed as providing conditions, parameters or valueswhich must be utilized exclusively in order to practice the presentinvention. Unless otherwise specified, all parts and percents are byweight.

EXAMPLE 1 Synthesis of triphenylsulfonium 5-iodooctafluoro-3-oxapentanesulfonate

12.56 grams (0.03 mol) of 5-iodooctafluoro-3-oxapentanesulfonyl fluoride(Synquest) was taken in a flask in water and excess amount of KOH (0.06mol, 3.31 grams) was added and the resulting mixture was heated understirring at 80° C. for six hours. To this reaction mixture (aftercooling to room temperature) was added 1:2 v/v THF/water solution oftriphenyl sulfonium bromide (0.03 mol, 10.14 grams) dropwise over aperiod of one hour with stirring. After the addition, the reactionmixture was further stirred for additional 3 hours at room temperature.Upon completion, the target compound triphenylsulfonium5-iodooctafluoro-3-oxapentafluoro sulfonate was extracted usingmethylene chloride. It was washed at least three times with DI water.Methylene chloride was evaporated to get a pale yellow liquid. It wasredissolved in methylene chloride and precipitated into hexanes. Yieldwas 82%. Melting point (capillary) 110-112° C.

EXAMPLE 2 Synthesis of bis(4-t-butylphenyl)iodonium5-iodooctafluoro-3-oxapentane sulfonate

9.93 grams (0.0233 mol) of 5-iodooctafluoro-3-oxapentanesulfonylfluoride (Synquest) was taken in a flask in water and excess amount ofKOH (0.0473 mol, 2.65 grams) was added and the resulting mixture washeated under stirring at 80° C. for six hours. After cooling thereaction mixture to room temperature, 5:1 v/v THF/water solution ofbis(t-butylphenyl)iodonium acetate (0.0233 mol, 10.56 grams) was addeddropwise over a period of one hour with stirring. After the addition,the reaction mixture was further stirred for additional 3 hours at roomtemperature. Upon completion, the target compoundbis(4-t-butylphenyl)iodonium 5-Iodooctafluoro-3-oxapentafluoro sulfonatewas extracted and purified in a manner similar to that of Example 1.Yield was 84%. Melting point (capillary) 118-122 C.

EXAMPLE 3

0.6318 g of poly(EAdMA/ECPMA/HAdA/α-GBLMA; 15/15/30/40) polymer, 0.062 g(143 μmol/gram) of triphenylsulfonium 5-iodooctafluoro-3-oxapentafluorosulfonate synthesized in Example 1, 0.0062 grams of N,N-diisopropylaniline (38.6% mol %), and 0.0204 g of 10 weight % PGMEA solution of asurfactant (fluoroaliphatic polymeric ester, supplied by 3M Corporation,St. Paul Minn.) were dissolved in 15.44 g of MHIB and 3.61 g of PGME.The solution was thoroughly mixed for complete dissolution and filteredusing 0.2 μm filter.

EXAMPLE 4

A silicon substrate coated with a bottom antireflective coating(B.A.R.C.) was prepared by spin coating the bottom anti-reflectivecoating solution (AZ® ArF-38, available from AZ Electronic Materials USACorp., Somerville, N.J.) onto the silicon substrate and baking at 225°C. for 90 sec. The B.A.R.C film thickness was 87 nm. The photoresistsolution for Example 3 was then coated on the B.A.R.C coated siliconsubstrate. The spin speed was adjusted such that the photoresist filmthickness was 130 nm, soft baked at 100° C./60 s, exposed with Nikon306D 0.85NA & dipole illumination using 6% half-tone mask. The exposedwafer was post exposure baked at 110° C./60 s, and developed using a2.38 weight % aqueous solution of tetramethyl ammonium hydroxide for 30sec. The line and space patterns were then measured on a AMAT CD SEM.The sensitivity to print 70 nm dense CD was 30 mJ, more than 0.20 nmDoF, with 3sigma LER/LWR values of 9 and 13 nm, respectively.

EXAMPLE 5

0.6208 g of poly(EAdMA/ECPMA/HAdA/α-GBLMA; 15/15/30/40) polymer, 0.0144g (30 μmol/g) of bis(4-t-butylphenyl)iodonium bis-perfluoroethanesulfonimide, 0.0256 g (60 μmol/g) of triphenylsulfonium5-iodooctafluoro-3-oxapentafluoro sulfonate synthesized in Example 1,0.0335 g (47 μmol/g) of bis[di(4-t-butylphenyl)iodonium]perfluorobutane-1,4-disulfonate, 0.0058 g of DIPA and 0.0204 g of 10weight % PGMEA solution of a surfactant (fluoroaliphatic polymericester, supplied by 3M Corporation, St. Paul Minn.) were dissolved in15.44 g of MHIB and 3.76 g of PGME to give a photoresist solution. Thephotoresist solution was filtered through a 0.2 μm filter.

EXAMPLE 6

A silicon substrate coated with a bottom antireflective coating(B.A.R.C.) was prepared by spin coating the bottom anti-reflectivecoating solution (AZ® ArF-38, available from AZ Electronic Materials USACorp., Somerville, N.J.) onto the silicon substrate and baking at 225°C. for 90 sec. The B.A.R.C film thickness was 87 nm. The photoresistsolution for Example 5 was then coated on the B.A.R.C coated siliconsubstrate. The spin speed was adjusted such that the photoresist filmthickness was 130 nm, soft baked at 100° C./60 s, exposed with Nikon306D 0.85NA & dipole illumination using 6% half-tone mask. The exposedwafer was post exposure baked at 110° C./60 s, and developed using a2.38 weight % aqueous solution of tetramethyl ammonium hydroxide for 30sec. The line and space patterns were then measured on a CD SEM. Thesensitivity to print 70 nm dense CD was 41 mJ, had more 6% EL, more than0.25 nm DoF, with 3sigma LER/LWR values of 6.36/10.38 nm with straightprofiles.

EXAMPLE 7

0.62 g of poly(EAdMA/ECPMA/AdOMMA/HAdA/α-GBLMA; 5/15/10/30/40) polymer,0.0144 g (30 μmol/g) of bis(4-t-butylphenyl)iodonium bis-perfluoroethanesulfonimide, 0.0256 g (60 μmol/g) of triphenylsulfonium5-iodooctafluoro-3-oxapentafluoro sulfonate synthesized in Example 1,0.0335 g (47 μmol/g) of bis [di(4-t-butylphenyl)iodonium]perfluorobutane-1,4-disulfonate, 0.0058 g of DIPA and 0.0204 g of 10weight % PGMEA solution of a surfactant (fluoroaliphatic polymericester, supplied by 3M Corporation, St. Paul Minn.) were dissolved in15.44 g of MHIB and 3.76 g of PGME The photoresist solution was filteredthrough a 0.2 μm filter.

EXAMPLE 8

A silicon substrate coated with a bottom antireflective coating(B.A.R.C.) was prepared by spin coating the bottom anti-reflectivecoating solution (AZ® ArF-38, available from AZ Electronic MaterialsCorporation, Somerville, N.J.) onto the silicon substrate and baking at225° C. for 90 sec. The B.A.R.C film thickness was 87 nm. Thephotoresist solution for Example 7 was then coated on the B.A.R.C coatedsilicon substrate. The spin speed was adjusted such that the photoresistfilm thickness was 130 nm, soft baked at 100° C./60 s, exposed withNikon 306D 0.85NA & dipole illumination using 6% half-tone mask. Theexposed wafer was post exposure baked at 110° C./60 s, and developedusing a 2.38 weight % aqueous solution of tetramethyl ammonium hydroxidefor 30 sec. The line and space patterns were then measured on a CD SEM.The sensitivity to print 70 nm dense CD was 41 mJ, had more 8% EL, morethan 250 nm DoF, with 3sigma LER/LWR values of 6.34/9.73 nm withstraight profiles.

EXAMPLE 9

0.6156 g of poly(EAdMA/ECPMA/HAdA/α-GBLMA; 15/15/30/40) polymer, 0.0144g (30 μmol/g) of bis(4-t-butylphenyl)iodonium bis-perfluoroethanesulfonimide, 0.0164 g (30 μmol/g) of bis(triphenylsulfonium)perfluorobutane-1,4-disulfonate, 0.0472 g (94 μmol/g) ofbis(4-t-butylphenyl)iodonium 5-Iodooctafluoro-3-oxapentane sulfonatesynthesized in example 2, 0.0065 g of DIPA and 0.0240 g of 10 weight %PGMEA solution of a surfactant (fluoroaliphatic polymeric ester,supplied by 3M Corporation, St. Paul Minn.) were dissolved in 15.44 g ofMHIB and 3.76 g of PGME to give a photoresist solution. The photoresistsolution was filtered through a 0.2 μm filter.

EXAMPLE 10

A silicon substrate coated with a bottom antireflective coating(B.A.R.C.) was prepared by spin coating the bottom anti-reflectivecoating solution (AZ® ArF-38, available from AZ Electronic MaterialsCorporation, Somerville, N.J.) onto the silicon substrate and baking at225° C. for 90 sec. The B.A.R.C film thickness was 87 nm. Thephotoresist solution for Example 9 was then coated on the B.A.R.C coatedsilicon substrate. The spin speed was adjusted such that the photoresistfilm thickness was 130 nm, soft baked at 100° C./60 s, exposed withNikon 306D 0.85NA & dipole illumination using 6% half-tone mask. Theexposed wafer was post exposure baked at 110° C./60 s, and developedusing a 2.38 weight % aqueous solution of tetramethyl ammonium hydroxidefor 30 sec. The line and space patterns were then measured on a CD SEM.The sensitivity to print 70 nm dense CD was 45 mJ, 6% EL, more than 250nm DoF, with 3sigma LER/LWR values of 7 and 11 nm, respectively, withstraight profiles.

EXAMPLE 11

Examples 3, 5, 7, and 9 can be repeated by substituting the polymertherein with one of the following polymers:

poly(2-methyl-2-adamantyl methacrylate-co-2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-α-gamma-butyrolactonemethacrylate); poly(2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate); poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate); poly(t-butyl norbornene carboxylate-co-maleicanhydride-co-2-methyl-2-adamantyl methacrylate-co-β-gamma-butyrolactonemethacrylate-co-methacryloyloxy norbornene methacrylate);poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-β-gamma-butyrolactone methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-methyl-2-adamantylmethacrylate-co-3,5-dihydroxy-1-methacryloxyadamantane-co-α-gamma-butyrolactonemethacrylate); poly(2-methyl-2-adamantylmethacrylate-co-3,5-dimethyl-7-hydroxy adamantylmethacrylate-co-α-gamma-butyrolactone methacrylate);poly(2-methyl-2-adamantylacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-α-gamma-butyrolactonemethacrylate); poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-methyl-2-adamantyl methacrylate-co-β-gamma-butyrolactonemethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-ethylcyclopentylacrylate);poly(2-methyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactone methacrylate);poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-α-gamma-butyrolactonemethacrylate-co-2-ethyl-2-adamantyl methacrylate);poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamantane-co-β-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-methyl-2-adamantyl methacrylate-co-2-ethyl-2-adamantylmethacrylate-co-β-gamma-butyrolactonemethacrylate-co-3-hydroxy-1-methacryloxyadamantane);poly(2-methyl-2-adamantyl methacrylate-co-2-ethyl-2-adamantylmethacrylate-co-α-gamma-butyrolactonemethacrylate-co-3-hydroxy-1-methacryloxyadamantane);poly(2-methyl-2-adamantyl methacrylate-co-methacryloyloxy norbornenemethacrylate-co-β-gamma-butyrolactone methacrylate);poly(ethylcyclopentylmethacrylate-co-2-ethyl-2-adamantylmethacrylate-co-α-gamma-butyrolactone acrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-isobutyl methacrylate-co-α-gamma-butyrolactone acrylate);poly(2-methyl-2-adamantyl methacrylate-co-β-gamma-butyrolactonemethacrylate-co-3-hydroxy-1-adamantylacrylate-co-tricyclo[5,2,1,02,6]deca-8-yl methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactone acrylate); poly(2-methyl-2-adamantylmethacrylate-co-β gamma-butyrolactone methacrylate-co-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamatane);poly(2-methyl-2-adamantyl methacrylate-co-methacryloyloxy norbornenemethacrylate-co-β-gamma-butyrolactone methacrylate-co-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamatane);poly(2-methyl-2-adamantyl methacrylate-co-methacryloyloxy norbornenemethacrylate-co-tricyclo[5,2,1,02,6]deca-8-ylmethacrylate-co-3-hydroxy-1-methacryloxyadamatane-co-α-gamma-butyrolactonemethacrylate); poly(2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-adamantylacrylate-co-tricyclo[5,2,1,02,6]deca-8-ylmethacrylate-co-α-gamma-butyrolactone methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactone acrylate); poly(2-methyl-2-adamantylmethacrylate-co-3-hydroxy-1-methacryloxyadamatane-co-α-gamma-butyrolactonemethacrylate-co-2-ethyl-2-adamantyl-co-methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactonemethacrylate-co-tricyclo[5,2,1,0^(2,6)]deca-8-yl methacrylate);poly(2-ethyl-2-adamantyl methacrylate-co-3-hydroxy-1-adamantylacrylate-co-α-gamma-butyrolactone methacrylate-co-2-adamantylmethacrylate); poly(2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-adamantyl acrylate-co-α-gamma-butyrolactonemethacrylate); and poly(2-ethyl-2-adamantylmethacrylate-co-3-hydroxy-1-adamantyl acrylate-co-α-gamma-butyrolactoneacrylate-co-tricyclo[5,2,1,02,6]deca-8-yl methacrylate)to form a photoresist solution. The photoresist solutions formedtherefrom are expected to give similar results as to those found inExamples 4, 6, 8, and 10.

EXAMPLE 12

Example 11 can be repeated by replacing triphenylsuflonium5-iodooctafluoro-3-oxapentafluoro sulfonate from Example 1 or replacingbis(4-t-butylphenyl)iodonium 5-iodooctafluoro-3-oxapentane sulfonatefrom Example 2 with one of the following: bis(4-octyloxyphenyl) iodonium5-iodooctafluoro-3-oxapentane sulfonate, [(4-octyloxyphenyl) phenyliodonium]5-iodooctafluoro-3-oxapentane sulfonate, (4-methylphenyl)phenyl iodonium 5-iodooctafluoro-3-oxapentane sulfonate,bis(4-methylphenyl) iodonium 5-iodooctafluoro-3-oxapentane sulfonate,(4-methoxyphenyl) phenyl iodonium 5-iodooctafluoro-3-oxapentanesulfonate, bis(4-methoxyphenyl) iodonium 5-iodooctafluoro-3-oxapentanesulfonate, 4-hydroxy-3,5-dimethyl dimethyl phenyl sulfonium5-iodooctafluoro-3-oxapentane sulfonate, (4-t-butylphenyl diphenylsulfonium) 5-iodooctafluoro-3-oxapentane sulfonate, bis(4-t-butylphenyl)phenyl sulfonium 5-iodooctafluoro-3-oxapentane sulfonate,bis(4-hydroxyphenyl) phenyl sulfonium 5-iodooctafluoro-3-oxapentanesulfonate, (benzoyltetramethylenesulfonium)5-iodooctafluoro-3-oxapentane sulfonate, (tris(4-t-butyl phenyl)sulfonium) 5-iodooctafluoro-3-oxapentane sulfonate,[bis[2-methyl-adamantylacetyloxymethoxyphenyl]phenylsulfonium]5-iodooctafluoro-3-oxapentane sulfonate,[bis[4-(3,5-di(trifluoromethyl)benzenesulfonyloxy)-phenyl]phenylsulfonium]5-iodooctafluoro-3-oxapentanesulfonate,[bis[4,4-bis(trifluoro-methyl)-3-oxatricyclo[4.2.1.0^(2,5)]-nonylmethoxyphenyl]phenylsulfonium]5-iodooctafluoro-3-oxapentane sulfonate, or,[bis[4-pentafluorobenzenesulfonyloxyphenyl]phenylsulfonium]5-iodooctafluoro-3-oxapentanesulfonate. The photoresist solutions formed therefrom are expected togive similar results as to those found in Examples 4, 6, 8, and 10.

The additional photoacid generators of formula (Ai)₂Xi1 can be made inaccordance with the procedures set forth in U.S. patent application Ser.No. 11/179,886, filed Jul. 12, 2005, and Ser. No. 11/355,762, filed Feb.16, 2006, the contents of which are hereby incorporated herein byreference. Other examples are found in U.S. patent application Ser. No.11/355,400, filed Feb. 16, 2006, United States Published PatentApplication 2004-0229155, and United States Published Patent Application2005-0271974, U.S. Pat. Nos. 5,837,420, 6,111,143, and 6,358,665, thecontents of which are hereby incorporated herein by reference. Thoseadditional photoacid generators of formula AiXi2 are well known to thoseskilled in the art, for example, those known from United States PatentApplication No. 20030235782 and United States Patent Application No.20050271974, the contents of which are hereby incorporated herein byreference.

The foregoing description of the invention illustrates and describes thepresent invention. Additionally, the disclosure shows and describes onlycertain embodiments of the invention but, as mentioned above, it is tobe understood that the invention is capable of use in various othercombinations, modifications, and environments and is capable of changesor modifications within the scope of the inventive concept as expressedherein, commensurate with the above teachings and/or the skill orknowledge of the relevant art. The embodiments described hereinabove arefurther intended to explain best modes known of practicing the inventionand to enable others skilled in the art to utilize the invention insuch, or other, embodiments and with the various modifications requiredby the particular applications or uses of the invention. Accordingly,the description is not intended to limit the invention to the formdisclosed herein. Also, it is intended that the appended claims beconstrued to include alternative embodiments.

1. A compound of the formula AiXi, where Ai is an organic onium cation;and Xi is anion of the formula X—CF₂CF₂OCF₂CF₂—SO₃ ^(—), where X isiodine; and where Ai is

where R_(1A), R_(2A), R_(3A), R_(4A), R_(5A) are each independentlyselected from Z, hydrogen, OSO₂R₉, OR₂₀, straight or branched alkylchain optionally containing one or more O atoms, monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms,monocycloalkylcarbonyl group or polycycloalkylcarbonyl group, aryl,aralkyl, arylcarbonylmethyl group, alkoxyalkyl, alkoxycarbonylalkyl,alkylcarbonyl, monocycloalkyloxycarbonylalkyl orpolycycloalkyloxycarbonylalkyl with the cycloalkyl ring optionallycontaining one or more O atoms, monocycloalkyloxyalkyl orpolycycloalkyloxyalkyl with the cycloalkyl ring optionally containingone or more O atoms, straight or branched perfluoroalkyl,monocycloperfluoroalkyl or polycycloperfluoroalkyl, straight or branchedalkoxy chain, nitro, cyano, halogen, carboxyl, hydroxyl, sulfate,tresyl, or hydroxyl; R₆ and R₇ are each independently selected from arylwhich is independently substituted by OSO₂R₉ or OR₂₀; R₉ is selectedfrom alkyl, fluoroalkyl, perfluoroalkyl, aryl, fluoroaryl,perfluoroaryl, monocycloalkyl or polycycloalkyl group with thecycloalkyl ring optionally containing one or more O atoms,monocyclofluoroalkyl or polycyclofluoroalkyl group with the cycloalkylring optionally containing one or more O atoms, ormonocycloperfluoralkyl or polycycloperfluoroalkyl group with thecycloalkyl ring optionally containing one or more O atoms; R₂₀ isalkoxyalkyl, alkoxycarbonylalkyl, alkylcarbonyl,monocycloalkyloxycarbonylalkyl or polycycloalkyloxycarbonylalkyl withthe cycloalkyl ring optionally containing one or more O atoms, ormonocycloalkyloxycarbonylalkyl or polycycloalkyloxyalkyl with thecycloalkyl ring optionally containing one or more O atoms; T is a directbond; Z is —(V)_(j)—(C(X11)(X12))_(n)—O—C(═O)—R₈, where either (i) oneof X11 or X12 is straight or branched alkyl chain containing at leastone fluorine atom and the other is hydrogen, halogen, or straight orbranched alkyl chain or (ii) both of X11 and X12 are straight orbranched alkyl chain containing at least one fluorine atom; V is alinkage group selected from a direct bond, a divalent straight orbranched alkyl group optionally containing one or more O atoms, divalentaryl group, divalent aralkyl group, or divalent monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms; R₈ is astraight or branched alkyl chain optionally containing one or more Oatoms, a monocycloalkyl or polycycloalkyl group optionally containingone or more O atoms, or aryl; j is 0 to 10; and n is 0 to 10, thestraight or branched alkyl chain optionally containing one or more Oatoms, straight or branched alkyl chain, straight or branched alkoxychain, monocycloalkyl or polycycloalkyl group optionally containing oneor more O atoms, monocycloalkylcarbonyl or polycycloalkylcarbonyl group,alkoxyalkyl, alkoxycarbonylalkyl, alkylcarbonyl,monocycloalkyloxycarbonylalkyl or polycycloalkyloxycarbonylalkyl withthe cycloalkyl ring optionally containing one or more O atoms,monocycloalkyloxyalkyl or polycycloalkyloxyalkyl with the cycloalkylring optionally containing one or more O atoms, aralkyl, aryl, naphthyl,anthryl, 5-, 6-, or 7-membered saturated or unsaturated ring optionallycontaining one or more O atoms, or arylcarbonylmethyl group beingunsubstituted or substituted by one or more groups selected from thegroup consisting of Z, halogen, alkyl, C₁₋₈ perfluoroalkyl,monocycloalkyl or polycycloalkyl, OR₂₀, alkoxy, C₃₋₂₀ cyclic alkoxy,dialkylamino, dicyclic dialkylamino, hydroxyl, cyano, nitro, tresyl,oxo, aryl, aralkyl, oxygen atom, CF₃SO₃, aryloxy, arylthio, and groupsof formulae (II) to (VI):

wherein R₁₀ and R₁₁ each independently represent a hydrogen atom, astraight or branched alkyl chain optionally containing one or more Oatoms, or a monocycloalkyl or polycycloalkyl group optionally containingone or more O atoms, or R₁₀ and R₁₁ together can represent an alkylenegroup to form a five- or six-membered ring; R₁₂ represents a straight orbranched alkyl chain optionally containing one or more O atoms, amonocycloalkyl or polycycloalkyl group optionally containing one or moreO atoms, or aralkyl, or R₁₀ and R₁₂ together represent an alkylene groupwhich forms a five- or six-membered ring together with the interposing—C—O— group, the carbon atom in the ring being optionally substituted byan oxygen atom; R₁₃ represents a straight or branched alkyl chainoptionally containing one or more O atoms or a monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms; R₁₄ andR₁₅ each independently represent a hydrogen atom, a straight or branchedalkyl chain optionally containing one or more O atoms or amonocycloalkyl or polycycloalkyl group optionally containing one or moreO atoms; R₁₆ represents a straight or branched alkyl chain optionallycontaining one or more O atoms, a monocycloalkyl or polycycloalkyl groupoptionally containing one or more O atoms, aryl, or aralkyl; and R₁₇represents straight or branched alkyl chain optionally containing one ormore O atoms, a monocycloalkyl or polycycloalkyl group optionallycontaining one or more O atoms, aryl, aralkyl, the group —Si(R₁₆)₂R₁₇,or the group —O—Si(R₁₆)₂R₁₇, the straight or branched alkyl chainoptionally containing one or more O atoms, monocycloalkyl orpolycycloalkyl group optionally containing one or more O atoms, aryl,and aralkyl being unsubstituted or substituted as above.
 2. Aphotoresist composition useful for imaging in deep UV comprising: a) apolymer containing an acid labile group; b) the compound of claim 1; andc) a compound selected from the group bis(4-t-butylphenyl) iodoniumtriphenyl sulfonium perfluorobutane-1,4-disulfonate,bis(4-t-butylphenyl) iodonium triphenyl sulfoniumperfluoropropane-1,3-disulfonate, bis(4-t-butylphenyl) iodoniumtriphenyl sulfonium perfluoropropane-1-carboxylate-3-sulfonate,bis(4-t-butylphenyl) iodonium triphenyl sulfoniumperfluorobutane-1-carboxylate-4-sulfonate, bis(4-t-butylphenyl) iodoniumtriphenyl sulfonium perfluoromethane disulfonate, bis(4-t-butylphenyl)iodonium triphenyl sulfonium methane disulfonate, bis(4-t-butylphenyl)iodonium triphenyl sulfonium perfluoroethane disulfonate,bis(4-t-butylphenyl) iodonium triphenyl sulfonium ethane disulfonate,bis(triphenyl sulfonium) perfluorobutane-1,4-disulfonate, bis(triphenylsulfonium) perfluoropropane-1,3-disulfonate,bis(benzoyltetramethylenesulfonium) perfluoropropane-1,3-disulfonate,bis(benzoyltetramethylenesulfonium) perfluorobutane-1,4-disulfonate,bis(tris(4-t-butylphenyl) sulfonium) perfluorobutane-1,4-disulfonate,bis(tris(4-t-butylphenyl) sulfonium) perfluoropropane-1,3-disulfonate,bis(4-t-butylphenyldiphenyl sulfonium) perfluorobutane-1,4-disulfonate,bis(4-t-butylphenyldiphenyl sulfonium) perfluoropropane-1,3-disulfonate,bis(triphenyl sulfonium) perfluoropropane-1-carboxylate-3-sulfonate,bis(triphenyl sulfonium) perfluorobutane-1-carboxylate-4-sulfonate,bis(benzoyltetramethylenesulfonium)perfluoropropane-1-carboxylate-3-sulfonate,bis(benzoyltetramethylenesulfonium)perfluorobutane-1-carboxylate-4-sulfonate, bis(tris(4-t-butylphenyl)sulfonium) perfluoropropane-1-carboxylate-3-sulfonate,bis(tris(4-t-butyl phenyl) sulfonium)perfluorobutane-1-carboxylate-4-sulfonate, bis(4-t-butylphenyl diphenylsulfonium) perfluoropropane-1-carboxylate-3-sulfonate,bis(4-t-butylphenyl diphenyl sulfonium)perfluorobutane-1-carboxylate-4-sulfonate, bis(4-t-butylphenyl iodonium)methane disulfonate, bis(triphenyl sulfonium) methane disulfonate,bis(4-t-butylphenyl iodonium) perfluoromethane disulfonate,bis(triphenyl sulfonium) perfluoromethane disulfonate,bis(benzoyltetramethylenesulfonium) perfluoromethane disulfonate,bis(benzoyl-tetramethylenesulfonium) methane disulfonate,bis(tris(4-t-butyl phenyl) sulfonium) perfluoromethane disulfonate,bis(tris(4-t-butyl phenyl) sulfonium) methane disulfonate,bis(4-t-butylphenyl diphenylsulfonium) perfluoromethane disulfonate,bis(4-t-butylphenyl diphenylsulfonium) methane disulfonate,bis(4-octyloxyphenyl) iodonium perfluorobutane-1,4-disulfonate,bis(4-octyloxyphenyl) iodonium ethane disulfonate, bis(4-octyloxyphenyl)iodonium perfluoroethane disulfonate, bis(4-octyloxyphenyl) iodoniumperfluoropropane-1,3-disulfonate, bis(4-octyloxyphenyl) iodoniumperfluoropropane-1-carboxylate-3-sulfonate, bis(4-octyloxyphenyl)iodonium perfluorobutane-1-carboxylate-4-sulfonate,bis(4-octyloxyphenyl) iodonium methane disulfonate,bis(4-octyloxyphenyl) iodonium perfluoromethane disulfonate,bis(4-octyloxyphenyl) phenyl sulfonium perfluorobutane-1,4-disulfonate,bis(4-octyloxyphenyl) phenyl sulfonium ethane disulfonate,bis(4-octyloxyphenyl) phenyl sulfonium perfluoroethane disulfonate,bis(4-octyloxyphenyl) phenyl sulfonium perfluoropropane-1,3-disulfonate,bis(4-octyloxyphenyl) phenyl sulfoniumperfluoropropane-1-carboxylate-3-sulfonate, bis(4-octyloxyphenyl) phenylsulfonium perfluorobutane-1-carboxylate-4-sulfonate,bis(4-octyloxyphenyl) phenyl sulfonium methane disulfonate,bis(4-octyloxyphenyl) phenyl sulfonium perfluoromethane disulfonate,bis[bis[4-pentafluorobenzenesulfonyloxy-phenyl]phenylsulfonium]perfluorobutane-1,4-disulfonate,bis[bis[4-pentafluoro-benzene-sulfonyloxyphenyl]phenylsulfonium]ethanedisulfonate,bis[bis[4-pentafluorobenzenesulfonyloxyphenyl]phenyl-sulfonium]perfluoroethanedisulfonate,bis[bis[4-pentafluorobenzene-sulfonyloxyphenyl]phenylsulfonium]perfluoropropane-1,3-disulfonate,bis[bis[4-pentafluorobenzenesulfonyloxyphenyl]phenylsulfonium]perfluoropropane-1-carboxylate-3-sulfonate,bis[bis[4-pentafluorobenzenesulfonyloxy-phenyl]phenylsulfonium]perfluorobutane-1-carboxylate-4-sulfonate,bis[bis[4-pentafluorobenzenesulfonyloxyphenyl]phenylsulfonium]ethanedisulfonate,bis[bis[4-pentafluorobenzenesulfonyloxyphenyl]phenylsulfonium]perfluoromethanedisulfonate,bis[bis[4-(3,5-di(trifluoromethyl)benzenesulfonyloxy)-phenyl]phenylsulfonium]perfluorobutane-1,4-disulfonate,bis[bis[4-(3,5-di(trifluoromethyl)-benzenesulfonyloxy)phenyl]phenylsulfonium]ethanedisulfonate,bis[bis[4-(3,5-di(trifluoromethyl)benzenesulfonyloxy)phenyl]phenylsulfonium]perfluoroethanedisulfonate,bis[bis[4-(3,5-di(trifluoromethyl)benzenesulfonyloxy)phenyl]phenylsulfonium]perfluoropropane-1,3-disulfonate,bis[bis[4-(3,5-di(trifluoro-methyl)-benzenesulfonyloxy)phenyl]phenylsulfonium]perfluoropropane-1-carboxylate-3-sulfonate,bis[bis[4-(3,5-di(trifluoromethyl)benzenesulfonyloxy)-phenyl]phenylsulfonium]perfluorobutane-1-carboxylate-4-sulfonate,bis[bis[4-(3,5-di(trifluoromethyl)benzenesulfonyloxy)phenyl]phenylsulfonium]methanedisulfonate, bis(4-t-butylphenyl iodonium) ethane disulfonate,bis(4-t-butylphenyl iodonium) perfluoroethane disulfonate, bis(triphenylsulfonium) ethane disulfonate, bis(triphenyl sulfonium) perfluoroethanedisulfonate, bis(benzoyltetramethylene-sulfonium) perfluoroethanedisulfonate, bis(benzoyltetramethylenesulfonium) ethane disulfonate,bis(tris(4-t-butyl phenyl) sulfonium) perfluoroethane disulfonate,bis(tris(4-t-butyl phenyl) sulfonium) ethane disulfonate,bis(4-t-butylphenyl diphenyl-sulfonium) perfluoroethane disulfonate,bis(4-t-butylphenyl diphenylsulfonium) ethane disulfonate,bis[bis[2-methyladamantylacetyloxymethoxyphenyl]phenyl-sulfonium]perfluorobutane-1,4-disulfonate,bis[bis[2-methyladamantylacetyl-oxymethoxyphenyl]phenylsulfonium]ethanedisulfonate,bis[bis[2-methyl-adamantylacetyloxymethoxyphenyl]phenylsulfonium]perfluoroethanedisulfonate,bis[bis[2-methyladamantylacetyloxymethoxyphenyl]phenylsulfonium]perfluoro-propane-1,3-disulfonate,bis[bis[2-methyladamantylacetyloxymethoxyphenyl]phenylsulfonium]perfluoropropane-1-carboxylate-3-sulfonate,bis[bis[2-methyl-adamantylacetyloxymethoxyphenyl]phenylsulfonium]perfluorobutane-1-carboxylate-4-sulfonate,bis[bis[2-methyladamantylacetyloxymethoxyphenyl]phenylsulfonium]methanedisulfonate,bis[bis[2-methyladamantylacetyloxy-methoxyphenyl]phenylsulfonium]perfluoromethanedisulfonate,bis[bis[4,4-bis(trifluoromethyl)-3-oxatricyclo[4.2.1.0^(2,5)]-nonylmethoxyphenyl]phenylsulfonium]perfluorobutane-1,4-disulfonate,bis[bis[4,4-bis(trifluoromethyl)-3-oxatricyclo-[4.2.1.0^(2,5)]-nonylmethoxy-phenyl]phenylsulfonium]ethane disulfonate,bis[bis[4,4-bis(trifluoromethyl)-3-oxatricyclo[4.2.1.0^(2,5)]-nonylmethoxyphenyl]phenylsulfonium]-perfluoroethane disulfonate,bis[bis[4,4-bis(trifluoromethyl)-3-oxatricyclo[4.2.1.0^(2,5)]-nonylmethoxy-phenyl]phenylsulfonium]perfluoropropane-1,3-disulfonate,bis[bis[4,4-bis(trifluoro-methyl)-3-oxatricyclo[4.2.1.0^(2,5)]-nonylmethoxyphenyl]phenylsulfonium]-perfluoropropane-1-carboxylate-3-sulfonate,bis[bis[4,4-bis(trifluoro-methyl)-3-oxatricyclo[4.2.1.0^(2,5)]-nonylmethoxyphenyl]phenylsulfonium]perfluoro-butane-1-carboxylate-4-sulfonate,bis[bis[4,4-bis(trifluoromethyl)-3-oxatricyclo-[4.2.1.0^(2,5)]-nonylmethoxyphenyl]phenylsulfonium]methane disulfonate,bis[bis[4,4-bis(trifluoromethyl)-3-oxatricyclo[4.2.1.0^(2,5)]-nonylmethoxyphenyl]phenylsulfonium]perfluoromethane disulfonate, bis(4-t-butylphenyl) iodoniumbis-perfluoroethane sulfonimide, 4-(1-butoxyphenyl)diphenylsulfoniumbis-(perfluorobutanesulfonyl)imide, 4-(1-butoxyphenyl)diphenylsulfoniumbis-(perfluoroethanesulfonyl)imide,2,4,6-trimethylphenyldiphenylsulfoniumbis-perfluorobutanesulfonyl)imide,2,4,6-trimethylphenyldiphenylsulfoniumbis-(perfluoroethanesulfonyl)imide,tris-(tert-butylphenyl)sulfonium-(trifluromethylperflurobutylsulfonyl)imide, tris-(tert-butylphenyl)sulfoniumbis-(perfluorobutanesulfonyl)imide,tris-(tert-butylphenyl)sulfonium-bis-(trifluoromethanesulfonyl)imide,and mixtures thereof.
 3. A process for imaging a photoresist comprisingthe steps of: a) applying on a substrate the photoresist composition ofclaim 2; b) baking the substrate to substantially remove the solvent; c)image-wise exposing the photoresist coating; d) optionally, postexposurebaking the photoresist coating; and e) developing the photoresistcoating with an aqueous alkaline solution.
 4. A coated substratecomprising a substrate with a photoresist coating film, wherein thephotoresist coating film is formed from the photoresist composition ofclaim 2.